Figure 2: Coupling variability across primary sensory areas and HP.
From: Coupled variability in primary sensory areas and the hippocampus during spontaneous activity
(a) Overall experimental design with freely behaving rats. (b) (top) Two seconds long samples of raster plots in time intervals with high and low cortical variability during spontaneous pre-exposure. (bottom) Corresponding 2 s long population firing rate plots of the raster plots found on (top) with the same color code after a 100 ms wide Gaussian kernel; the vertical bar corresponds to spikes/neuron/second. (c) Example of the CV of the population activity in each brain area: in S1 (green, n = 16), V1 (blue, n = 22) and HP (orange, n = 13) across different behavioral states; vertical black dashed lines delimit the exposure time period. The shading color code informs the behavioral states throughout the experiment, where each data point was calculated from 10s-long periods of population activity. (d) Scatter plots of pairs of CVs in each brain area shown in (a) segmented by selected behavioral states (WK,SWS and REM); also indicated is the Pearson correlation coefficient, r, between the CVs in each behavioral state. (e) Boxplot of group data for the Pearson correlation coefficient between CVs found in each pair of brain area during all experiments (8 datasets); all pairs had a significant correlation in CV with a significant difference only between S1V1 and S1HP. (f) Example of CV of the population activity segmented by behavioral states. (g) Samples of spiking correlations for 5 min long pre-experience time periods with different levels of cortical variability: (left) local spiking correlation histograms within S1, V1 and HP; (left-top) mean spike correlations for high levels of cortical variability; (left-bottom) mean spike correlations for low levels of cortical variability; (middle) inter-area spiking correlation histograms; (middle-top) mean spike correlations for low levels of cortical variability; (middle-bottom) mean spike correlations for low levels of cortical variability; (right, top and bottom) respective correlation matrices of the data.
